Tuesday, December 08, 2009

Clash of the Dinosaurs: Highs & Lows


The Discovery Channel started a new dinosaur series on Sunday called, um, Clash of the Dinosaurs. I think it discusses new ideas about dinosaur biology and evolution, I'm not really sure. I watch it for the talking heads, honestly, who are people I know and have met, which is awesome. I urge you to watch the first episode and make your own determination, but here's my rundown of the pros and cons.

In the Green Corner...

1. The dinosaurs look really nice. Tyrannosaurus, Triceratops, Sauroposeidon, Deinonychus, and Quetzelcoatlus are the stars and the artists put some time and effort into these critters. For the first time since I can remember, these TV-special-calibur CG dinosaurs look better than the beasties in Walking With Dinosaurs, a benchmark I've been hoping somebody will overcome for the better part of a decade. They even put (some) feathers on the raptors, so there you go.

2. They had an animation of Quetzelcoatlus landing...and then taking off! You better believe I rewound and replayed those sequences about five times each. Easily the highlight of the episode for me. The rest was pretty standard dinosaur vs. dinosaur fare. And hey, then the big pterosaur chowed down on a baby T.rex, so bonus points all around!

3. Thomas Holtz bringing the smackdown to T.rex as a scavenger (briefly). Always appreciated. I can't help but notice and be amused by the fact that he and Bakker are now the go-to guys for T.rex, but Horner was nowhere to be found. A welcome change!

4. Matt Wedel really likes Sauroposeidon, and explains the hazardous life history of giant sauropods really, really well.

5. The T.rex bit off the Trike's postorbital horn! AWESOME! And then it got stabbed in the eye (and, from the looks of it, brain)! YET MORE AWESOME! I winced, internally. Look, folks! They're basing their behavior animations on fossil evidence now! Another bridge has been crossed.

In the Red Corner...

1. Limited animation sequences repeated endlessly. How many times do I have to see the same X-ray view of T.rex sniffing the air? How many dinosaurs is that baby T.rex going to fall out of its egg? How many times do I get to see that angry Triceratops bellow? About a million each, apparantly.

2. Everybody is ga-ga for raptors hunting in packs. It's a hypothesis, sure, but I was hoping that somebody would bring up that one study that convincingly suggested that they were more like varanids than canines. That analogy WAS applied to T.rex, but in a throw-away manner.

3. They show kept pounding away at the idea that T.rex was some sort of Einstein among dinosaurs, but then concluded by saying they were all morons who got along thanks to their physical adaptations (they didn't need to be smart). Make up your mind, Discovery Channel. For whatever reason, they pulled "four miles away" out of their ass for "how far away T.rex could see things." The implication being that "things" means "prey items." I'm doubting that. A mountain? Sure. A Trike? Maybe not.

4. Are those hatchling sauropods rising from a sandy nest, or adults moving through a sand dune? It's hilariously unclear.

5. Sauropods had no way of defending themselves from attack? How about kicking, tail-whipping, or stomping? The juvenile Sauroposeidon, which looked about as big as an Astrodon given the trees around it, just kinda stood there while the raptors tore it apart.

6. Dinosaurs are no daikaiju. You don't need to slow their motion down to impart a sense of size. In reality, big animals are very capable of making incredibly fast movements. Have you ever seen a spooked (or pissed-off) elephant? That sucker makes unbelievably quick movement. Jerky, reflexive motions. The same principle can be applied to dinosaurs, but you never see it. Not here, not anywhere.

So that's the rundown. Again, I encourage you to watch it because overall it's quite good. Since it's a cable network, it's probably on at least once a day, so it shouldn't be too hard to catch a repeat.

30 comments:

Nima said...

Great breakdown of the show, Zach! I was wondering about those dune-climbing Sauroposeidons too! They had adult proportions, but were supposed to be hatchlings?

Furthermore, I was also cheesed off by a couple of things they said that have NO basis:

1. "Sauroposeidon had a cheeseburger brain". It wasn't big, but it wasn't a wimpy 99 cent cheeseburger either. First of all, that nice little 3D brain they showed is not so real - nobody's EVER found the head of Sauroposeidon, the only remains are 4 neck vertebrae. The skull in the 3D model was an exact copy of Giraffatitan/B.brancai. And I don't even think they scaled it correctly .

Then the brain itself.... I don't think this is actually a model of Giraffatitan's brain either. I've NEVER seen any published material on the shape of the brain of ANY brachiosaur, to my knowledge no scan on them has ever been done. Sis they just steal a Diplodocus brain scan?

Finally, even Giraffatitan had a brain that was more the size of a large potato than a 1-patty cheeseburger. Still tiny for that huge body, but comparable in size with many mammal brains today. Sauroposeidon, being bigger, should have had a bigger skull and at least a slightly larger brain.

2. "Sauroposeidon was as dumb as a fencepost" - this is hard to demonstrate when you don't actually have the skull to take a scan or an endocast, and you don't even have one for Giraffatitan either! These 3D models were done by Larry Witmer's Lab (Witmer made the fencepost comment on the show) and there's not a single picture or publication on the lab's website associated with brachiosaurs of any sort. His only sauropod brain scans on the site are of Nigersaurus, and it's not the same brain shape used for Sauroposeidon in the show. So what parts of Sauroposeidon's brain were REALLY developed, and whether it had some sort of intelligence, are UNKNOWN.

IMO, it wasn't THAT dumb. It had to think at least to survive, find food and water, etc. Could it process more than one thought at a time? Doubtful, heck even some humans have trouble with that! Could it communicate? Yes. Could it form complex strategy? Probably not. But this creature must have had something more than instinct. Even primitive lizards today can learn a few things, and dinosaurs had far more advanced brains.

3. "They didn't rear their young"

This is a common myth that used to be thought true of ALL dinosaurs in the 1920s - they were cold-blooded idiots that just abandoned their eggs and moved on. Even snakes and gators care for the eggs until they hatch. Did warm-blooded dinosaurs lack even this basic instinct? Forget about incubation with your body - just drop some plants over the nest to trap heat! In the show they just left a BARE NEST open for predators to come devour the eggs! No wonder Matt Wedel claims on the show that out of thousands of babies "only two or three" survive to adulthood - with the kind of half-assed nest-digging the animation showed, I'm surprised ANY survived at all. I don't really agree with Matt's conclusion either. Sauroposeidon is only known from four adult cervicals, so any speculation about the babies is just that - speculation.

Nima said...

4. "we never find sauropod babies together with the adults" - Actually, paleontologists rarely find sauropod babies at all. There's a good reason for this: most either grew up, or got digested by meat eaters! Now what percent grew up and what percent were digested, is totally up in the air. It mostly depends on how big the sauropods populations were - did they have huge herds like wildebeest today, or were there smaller groups like elephants? Then the reproductive strategy: did they lay hundreds of eggs each year, or only a handful?

Another thing - it's NOT hard to care for plant-eater hatchlings. Maybe their first meal will have to be brought to them, but as soon as they can walk, they can start munching on ferns without any help. By comparison, duckbill babies were weaker and probably spent more time in the nest - but meat eaters like T. rex probably invested the MOST time in their offspring, since hunting is MUCH harder to learn than eating plants.
So it's not all that hard to imagine Sauroposeidon raising their young - it's insanely easy. Throw them a few tree fern branches, let them loose to munch on the forest floor, and stick around for a while to scare off the small predators. Within a month they'd be big enough to keep up with the herd without tiring themselves out.

The reason babies and adults are not often found together is simple - nests and babies that got fossilized were probably buried by small-scale seasonal sandstorms or floods - things that the big adults could survive, but were unable to save all their babies from. If they simply left their nests OPEN and abandoned them, the eggs would have been EATEN, not fossilized. Yet complete nests of sauropod eggs are pretty abundant and uncracked in the few places where they do turn up.

In fact, if you assume they were watched over by adults and soon were traveling within the herd, THAT explains why babies and adults are rarely found together - the babies didn't die as babies, they grew up and mostly died as adults, thanks to the protection of the herd. There are trackways that indicate this protective behavior as well. Those that DID get eaten obviously were not fossilized.

Will we ever find concrete proof of nurturing sauropods to back up this circumstantial evidence? Aside from the extant trackway evidence of young sauropods flanked by adults in Paluxy and elsewhere, the best solid proof would be a bonebed where a herd of all different sizes died. However, even this method is vulnerable to error! The BIG flash floods that often created bone beds could have easily carried the little babies off for a far longer distance than the 30+ ton adult carcasses, where they would have been washed up on the riverback rather than buried in silt on the bottom. And washed-up baby dinosaurs are a cheap easy snack for scavengers of ANY size - say goodbye to fossilization. Tendaguru has Giraffatitan adults and subadults of various sizes, but no juveniles - they might just as easily have been washed out to sea, or gobbled up by crocodiles! Finally there's just too little of Sauroposeidon known to tell how it lived. End result: even the best sauropod bone beds can lack babies for a whole host of reasons that have nothing to do with "egg neglect".

Nima said...

FINALLY, the whole scene with the Deinonychus attack was total BS. That young Sauroposeidon was the size of an Astrodon, not a Polar Bear. Those raptors were far too small to take down something like that - hell, they can't even jump that high! But in the show they were jumping all over its neck and shoulders, and after a few cuts it fell. There was barely any time for blood loss, and no vital organs were hit. And the thing didn't move its tail or stomp or anything!

This is not the defensive behavior of a REAL herbivore. Elephants will dash away and even maul a much faster predator if it comes to that.

Sauropods had claws for a reason, and it was NOT just digging nests. It would take a pack of five or six full-sized Utahraptors to defeat something that big, not two little Deinonychus. Raptors didn't tackle sauropods, they weren't built to handle something that huge. For that, there was always Acrocanthosaurus!

davidmaas said...

You guys have video clips to share with us poor Europeans?

Zachary said...

Definately agree on all counts. Now, I'm a little skeptical of sauropods rearing their young, not so much because I don't believe it happened, but Auca Muevo demonstrates that in titanosaurs at least, there were tons and tons of babies that probably all hatched alone and ran off into the woods. But yeah, the nests were just totally uncovered! Oh please! Kick some damn sand over those eggs, you idiots!

The sauropod skull they showed was Camarasaurus, definately. The brain was probably Camarasaurus, too. Close to Sauroposeidon, but of course, there's no skull for Oklahoma's biggest brachiosaur. In general, Sauroposeidon may have simply been a bad choice. Why not use Brachiosaurs/Giraffititan? Why the focus on North American dinosaurs at all?

We know more about the baby-rearing strategies of Allosaurus, for crying out loud. But eeeeeverybody loves T.rex. *groan*

Zachary said...

Dave, I can only imagine it's on Hulu or the Discovery Channel website...I don't know how to post videos other than on YouTube. *sigh*

Nima said...

I'd say the only reason they chose Sauroposeidon was SIZE. It's simply bigger than good old Brachiosaurus. That, and brachiosaurs didn't get much airtime on Walking With Dinosaurs (count 'em, TEN seconds!). So it's a welcome change, but it has its own new set of problems!

I'm glad they got the hands and feet right, and also the tail's in the air, but those necks are too short for Sauroposeidon. The necks are no longer than the height of the shoulders from the ground, so head height is double shoulder height. This average-sized sauropod neck is short even for B. altithorax, IMO, LET ALONE Sauroposeidon.

And I agree, they were lurching and stomping a bit too much IMO just for normal walking movement. I'd like to see faster sauropods next time, Sauroposeidon was 50-60 tons MAX, let's leave the daikaiju stomping for TRULY legendary creatures like the 100-ton Puertasaurus.

The skull they used seems to be Giraffatitan, not Camarasaurus - the model has a snout that sticks out well beyond the nasal crest, and the head of the live animal in the show is definitely brachiosaurid, almost an exact copy of Raul Martin's Brachiosaurus. But the brain model probably IS Camarasaurus because that's been scanned, and Giraffatitan has not. Camarasaurus had a smaller skull and probably a smaller brain as well.

As for the eggs... I'm not saying sauropods must have cared for their young, but that it's plausible and actually quite easy to do. Sauropod babies didn't need all that much pampering, based on the embryo remains in Auca Muevo and the Neuquen formation, they could probably walk within a few hours of hatching.

The question is, HOW did all those babies and eggs get killed and fossilized? Sandstorm? Mud? Flood? Whatever it is seems to have spared the adults - and prevented them from walking into the forest. So either the adults did care for the babies, or at least hid the eggs!

Sheesh, the Discovery guys must have been really stoned this time, at least the BBC showed Diplodocus laying eggs in a dense forest and covering them with leaf litter, where they'll have easy acces to food AND shelter to hide from predators. Discovery Channel shows Sauroposeidon laying eggs in an open depression, BARELY even deep enough to be called a pothole, in some barren plain where there's no real foliage for miles! Even if those exposed eggs to hatch, where would the babies hide and what would they eat?

If they want to show dinosaurs abandoning their babies like in the cold-blooded children's books of fifty years ago, AT LEAST show them doing it correctly and in the right place!

Are the Discovery folks trying to say that sauropods didn't even have as much brains as a sea turtle, which despite having no access to foliage, at least HIDES its eggs in sand before abandoning them?

Is it just me or are the producers every dinosaur special since the year dot, just desperate as hell to convince us that sauropods were somehow pathetic weaklings that shouldn't have evolved at all? When Matt Wedel talks about a pack of Deinonychus killing a POLAR BEAR-sized BABY Sauroposeidon, and the animators show TWO measly Deinonychus jumping up the height of five Shaq's and taking down a sub-adult the size of FIVE ELEPHANTS, it's pretty obvious the producers are the real cheeseburger-heads here. Anything to make a fight scene look more ridiculous, fake, and lopsided... that's American entertainment for you. Even when it's laced with a tinge of science. And yet we still wonder why everyone says wrestling is fake - heck, WWF is easily a hundred times more real than what they showed those raptors doing! I bet Discovery hired the same over-the-top guys that worked on 300, damn they can't even seem to get the basic mass physics right!

Trish said...

Nima: "'We never find sauropod babies together with the adults' - Actually, paleontologists rarely find sauropod babies at all."
Zack: "Auca Muevo demonstrates that in titanosaurs at least, there were tons and tons of babies that probably all hatched alone and ran off into the woods."

Ever since "Walking With", I was wondering where the heck they got the "Sauropods are basically sea turtles on land" thing. It always struck me as a little strange. (Err... not just because I am an original "Land Before Time" fangirl.) Now I'd like to hear them explain/justify the "WWD" Diplodocus sporting an ovipositor that would shame the Alien Queen.

Sounds like an interesting series, but the warning about stock animation sours the appeal for me. Trust me, I know animation takes a lot of effort, but there are better solutions to economize than "Nobody will notice if we show the same animation of that one guy talking over and over."

Nima said...

I think the "sauropod sea turtle" thing is pretty lame too. There's good fossil and physical evidence that all dinosaurs, sauropods included, were warm-blooded and exhibited herding behavior where herds included juveniles.

Now, warm-blooded in sauropod terms did NOT mean racing at hanmster pace and panting like crazy in ten milliseconds. Warm blooded sauropods would still be slow, just a bit LESS slow than Discovery or even BBC tend to show them. Smaller warm-bloods have a faster heartbeat and more amped-up metabolism because their small size loses heat quickly. Bigger warm-bloods like elephants have a much slower metabolism and produce a lot less excess heat per pound as their large bodies retain heat, but they still generate their own heat internally. Such would have been the case with sauropods, only better. Greg Paul's Terramegathermy paper also punches a huge hole in any notion that cold-blooded "gigantothermy" is even plausible in animals over a ton. After that, the cold-blooded paleontological camp pretty much dropped the ball and stayed silent.

Thus, warm-blooded herding and nesting behavior is not just plausible but even likely IMO. And even if you look at dinosaur's closest cold-blooded relatives, the crocodylians, they all hide and care for the eggs until they hatch, and even protect the babies for a while after that. So at the VERY least sauropods would have done this. The true reptiles (lizards, crocs, snakes...) for all their flaws are better parents than the more primitive anapsids (such as turtles).

I think sauropod babies imprinted on a parent, not a place like sea turtles do. This would have helped them spread across the globe and evolve to match local conditions fairly quickly, as the fossil record suggests, whereas turtles return only to the same beach year after year after year.

There's also the myth of Zigongosaurus laying some elongated eggs in the sand in a double line and just leaving them there, this is a popular myth that's been repeated ad nauseum in popular books, but I've never seen any concrete proof for it. Even if a line of eggs were found, it's impossible to assign them to Zigongosaurus or anything else without adult remains accompanying them. And finally, sauropods to the best of our knowledge always laid spherical eggs, not elongated ones like the myth claims.

The fact is, every fossil sauropod egg was found in a covered nest, the sandstone was the same above and below the eggs, and it had to be removed to excavate the eggs. Now since they got fossilized there was either a sandstorm or a small flood that buried the eggs/babies, either way it does not disprove that the parents NORMALLY raised the babies in cases where freak disasters did not bury them first. If the eggs were simply abandoned and got eaten, there would be no fossil evidence to prove that. So whether the parents always abandoned their eggs, or simply failed to rescue them from a small flood that killed babies but spared adults, is impossible to know conclusively.

Eric said...

Haven't they found sauropod tracks that show that sauropods were age segregated? Does seem like a convincing argument that they didn't really practice parental care. Of course it's really hard to classify parental care (if you mean they watched their eggs then I would agree since some modern reptiles practice it. Although I would imagine that sauropods would outpace their hatchlings in their search for taller trees but that is a flimsy argument.

Also it's not that hard for carnivours reptiles to hunt pretty much from birth. Snakes, crocodilyians, and kommodo dragons (maybe other monitors as well) do i, true they feed mainly on insects and other small critters but still.

Maybe we just need more evidence, preferably a time machine.

"FINALLY, the whole scene with the Deinonychus attack was total BS"

I agree. What is it with most incarnations of Deinonychus/"Raptors" in showing them are invincible predators capable of taking down large prey easily. Which is funny since even lions have to really struggle to bring down Wildebeasts. And as Planet Earth shows it takes about 15-20 lions to bring down an elephant so it must take a ton of Deinonychus to bring down a juive Sauroposeidon.

Matt Martyniuk said...

"There's good fossil and physical evidence that all dinosaurs, sauropods included, were warm-blooded and exhibited herding behavior where herds included juveniles."

Not so. In fact this seems to vary among sauropods. Some titanosaur trackways show mixed-aged herds, but no very small individuals. Some trackways clearly show only adults moving together. Several recent papers have argued that sauropods did not exhibit parental care, simply because an adult sauropod would be incapable of manually feeding its many nestlings and itself, and hatchlings could not eat the same food as adults in most cases.

Given the huge size of sauropods and the number of eggs per nest, they must have been r-selected. Its difficult to imagine any ecosystem that could support dozens of new sauropods reaching adulthood each year.

Meyers & Fiorillo 2009 is a good recent overview of all this.

Nima said...
This comment has been removed by the author.
Nima said...

Some tracks seem to show age segregation, others show mixed-age herds. It depends on the species. However, I'd reckon that all sauropods cared for their young at least until they could FORM an age-segregated herd that had any chance of survival. Sauropod babies don't look all that high maintenance based on preserved embryos: they could probably feed themselves within hours. Again caring for baby sauropods is not that hard, and age segregation doesn't disprove it - it only proves that the different age groups fed in different areas which probably had different sorts of plants, thus they didn't compete for the same food. Size of the plants matters too. In locales where the food plants were not all one size or type, age segregation was not as necessary.

Sauropods may have been neither r-selected nor k-selected in some cases, but something in between. Though I agree that in some more basal cases like Shunosaurus and Bellusaurus, r-selection is much more common. Diplodocids too. Brachiosaurus seems relatively more k-selected, but certainly not as much as large mammals today. The huge nesting colonies of titanosaurs show "arrested" r-selection - that is, eggs were NOT simply abandoned any old place, and organized communities of parents that probably cared for their babies for a while but soon left them to their own devices, similar to Maiasaura as described by Horner and Gorman, but with the process sped up a bit. They grew up fast and joined a new herd.

As for the Deinonychus - yeah, everyone's so in love with raptors that they forget raptors were fairly slender and weak as far as predators go. They sacrificed power and bulk for speed, claws, and balance. Their little jaws and teeth may have been sharp, but they were far too small to make a dent in a big sauropod - I mean, we'd be talking a BIG pack of Utahraptors here if you want to see even a CHANCE of a sauropod kill. And that would still have to be a very SMALL, elephant-sized sauropod kill.

Raptors of any sort are lightly built and can easily be swept aside into a tree, crushed, or suffer broken ribs from just a twitch of a sauropod's tail. Their claws, deadly to a smaller herbivore, probably could not penetrate deep enough to hit a sauropod's internal organs or major arteries - again, only something as big as Utahraptor would even have a half decent shot. The only predators that would normally go up against even a half-grown sauropod are big bulky carnosaurs like Acrocanthosaurus which actually had the heavy duty skull and teeth to really do some damage to a sauropod, and even those guys probably stayed away from Sauroposeidon - why bother attacking it when Pleurocoelus/Astrodon and Cedarosaurus are a much more manageable size????

All the fossil EVIDENCE shows that Deinonychus preferred to attack Tenontosaurus and other beaked plant eaters of the time, which were smaller and easier to tackle than a sauropod. Still not easy though. Even though 'Jurassic Fight Club' forgot to give their raptors feathers, at least it showed SOME of the Deinonychus getting crushed and killed by the Tenontosaurus. Plus, Tenontosaurus didn't even HAVE any weapons, even the tail was more like a stiff, clumsy balance beam than a precision whip. And its thick hide was a real obstacle for the raptors - even that is still a much easier target than a sauropod, which has a flexible tail, triple foot claws, a pretty mean thumb claw, far greater height, and grows many times bigger than the biggest Tenontosaurus even as a youngster.

And I know this is redundant, but those raptors could not jump that high, you'd swear they were fleas! Literally, in the show they jump five times as high as Shaq! (and by that I mean five times Shaq's jumping head height at the moment when he's IN THE AIR).

Come on, Discovery. Give us a break with the theropod-worship already. Raptors weren't invincible, and they weren't killing everything in sight - only what was small and weak enough for a BIG PACK of them to rip apart with a few well placed slashes. That Sauroposeidon was way out of their league.

Matt Martyniuk said...

"Though I agree that in some more basal cases like Shunosaurus and Bellusaurus, r-selection is much more common. Diplodocids too. Brachiosaurus seems relatively more k-selected, but certainly not as much as large mammals today."

How can we know this for species with no preserved nests, or even juvenile specimens of any kind?

What makes Brachiosaurus more k-selected than diplodocids? What makes diplodocids more r-selected? Why are primitive forms more r-selected? I'm curious which lines of evidence explain all this. Any papers?

Nima said...

Shunosaurus and Bellusaurus are known from age segregated herd remains. Bellusaurus is ENTIRELY known from juvenile remains!

Diplodocid trackways do not show much range in individual size, but brachiosaur trackways (like the "Brontopodus" prints sometimes referred to Pleurocoelus) do show a range. There are no super-small baby prints, but they weren't big or heavy enough to leave any prints that would survive mud cave-in. There's already a good bit of that around the biggest adult prints. But there are prints in the center of herd trackways in the juvenile range. This pattern is too distinct to be simply the little sauropods crossing the same spot as the big ones at a later time.

Brachiosaurus altithorax remains (and Brachiosaurus sp. referred remains) are far rarer than diplodocid remains in the same formation, this is an indicator of k-selection, fewer offspring, etc. They would still have faced threats from predators, since k-selection does not guarantee survival. But then again, as well known as the Morrison is, it's still bound to hold more Brachiosaurus. It just seems to be a lot rarer and perhaps had fewer babies and invested more time in them. I'm not claiming any of this is certain, but if anything the breeding like rabbits strategy would have worked fine for diplodocids (and MAYBE even for Giraffatitan, but that's debatable).

But you do pose an interesting point - WHY are there no known egg or nest fossils from Morrison sauropods? Did they all just take their babies with them on the go? Why was even one nest not buried and fossilized? Did they all just nest in high-elevation areas that silt and mud could never reach, and then go back to the lowlands? Was Brachiosaurus a k-strategist confined to the nest-friendly highlands, or did it mingle with Diplodocus in the valleys and floodplains?

I'm really craving that time machine right about now...

Nima said...

Furthermore there are some baby Apatosaurus and Diplodocus remains known (REAL babies, smaller than a human), but no baby Brachiosaurus remains. Did these guys just grow up far from rivers and flood-prone areas, or did their parents keep them away from dangerous waters and loose sediment? Let's remember, most Morrison sediment is flood sediment, the creatures that DID get fossilized there likely drowned or were washed together halfway through being scavenged. Neither of these possibilities explains the absence of baby brachiosaurs. Were baby brachiosaurs hunted or scavenged less commonly than other types, that not even a partial carcass made it into a flood? Were there simply fewer of them to begin with? Or did the adults get between them and the carnivores? And let's remember, carnivores tend to stick close to rivers, because that's where the prey often is.

In the final analysis, it's a bit odd that if Brachiosaurus was r-selected, not even a single baby specimen is known. Statistically, there should be enough of them to have at least a few get drowned in a flood and preserved, as with Apatosaurus and Diplodocus... IF they were r-selected that is. Maybe more digging needs to be done before a baby is found - but then why are ADULT Brachiosaurus remains so rare after a century of excavation?

Anonymous said...

Of course, whose to say that sauropods didn't have crecheing behavior, like ostriches? A few adults get all the little sauropod babies dumped on them by the others in the herd, and then just stick around in the general area to make sure they aren't all wiped out by some maurauding troodont. Of course, it would be more like the extent alligators care for their young, seeing the size disparity between the juvenile and the adult. Some evidence that might support this (might) is the presence of creching behavior in dinosaur cousins (I'm looking at you, ratites), dinosaur cousins raising young much smaller than they were (alligators and other crocodilians), and inferred creching behavior in other dinosaurs (the "Proctor Lake Ornithopods" in Texas). I also heard somewhere that there was some evidence that a handful of Auca Mahuevo sauropods stuck around, but I forget where I heard this.

Though I'm a bit doubtful at the way they always seem to build nests in dinosaur documentaries. They seem to just lay their eggs in straight lines, or just drop them in a hole. I mean, even sea turtles cover their eggs with sand for goodness sake!

"egg or nest fossils from Morrison sauropods?"

There actually are some eggs in the Morrison formation, including some associated with a couple sauropod skeletons. No indication if they were from the sauropods, however.

As for the Deinonychus as a varanid theory, I seriously have to doubt that. First off, if it was just a bunch of dinosaurs associating around a carcass, then why are they only one species? If you see a kill on the African savannah, it doesn't just bring in lions, it brings in hyenas (or vice versa) and vultures too. And with dinosaurs leaving shed teeth everytime they ate, what's to stop an Acrocanthosaurus from just coming along and scaring the raptor pack off its kill.

Not to mention that group hunting behaviors are seen in more than just canids. Hyenas hunt in groups, as do lions, harris hawks, orcas, and other animals. Dinosaurs were taking the niche of megafauna that mammals took in the Cenozoic, so its not that unusual to assume that some theropods had pack-hunting behaviors. I mean just because dinosaurs are reptiles does not make them lizards.

Nima said...

Creching behavior is only NATURAL for dinosaurs as it is for many other animals. The little ones stick close to a few big ones while the rest go and get food. Getting food for baby sauropods is easy, just bend your neck down, tear off some ferns and bring them back to the nest. In a few hours the babies can walk out of the nest and eat their own ferns. But they'll still need a few adults around for protection. And I've heard of the Auca site having some adult remains as well.

John Sibbick's painting of Aucasaurus distracting the adults and raiding their nests is a very interesting idea in itself.

I'm just sick of this whole "sauropods were dumb as a doorknob" theory that is regurgitated every few years. Yeah they had small brains and probably a herd-groupthink mentality. So what? If anything this makes the babies MORE likely to stick close to the adults that they imprint on.

At least they should be show digging a PROPER nest that's covered up to hide and WARM the eggs... and the nest should at least be SOMEWHERE near a forest. Most sauropods made a roughly circular nest, to my knowledge only ONE site in Romania shows them laying lines of eggs, and the lines are very SHORT, like 3 or 4 eggs in a line, and then they covered them with sand and laid 3 or 4 more several meters away (this may have been to confuse predators, not put all your eggs in one basket, etc.... which in my book is pretty SMART for a "cheeseburger brained" animal...)

This Romanian site still does NOT explain why so many crappy books claim that Zigongosaurus (did they just choose this genus randomly out of a hat?) laid HUNDREDS of eggs in a line AS IT WALKED and didn't cover them up.... Zigongosaurus was in China, where there are no such "egg lines" and in fact, NOWHERE in the world has there ever been found a long line of hundreds of dinosaur eggs...

They should focus more on what dinosaurs DID with their brains, rather than just their small size. Brachiosaurus' brain was bigger than a cat's brain. So if we're going just on size (which isn't very reliable) it should be at least as intelligent as a cat, and had behavior at least as complex, which is not too bad for 150 million years ago...

Sometimes the desire to describe freaky and unbelievable things overcomes the desire to communicate SOLID science. Of course if cryptozoological sensationalism is their cup of tea, I'd advise book publishers that Bat Boy rakes in much better sales than "egg-line-Zigongosaurus".

Nima said...

As for the raptors... I don't buy the varanid hypothesis at all. Raptors were pack hunters. They had the brain power, and all the evidence shows they brought down Tenontosaurus and ate the flesh, before any other carnivores could get to it. Komodo Dragons are a freak exception - they're just lucky there aren't any big pack-hunting mammals on their island, otherwise the competition would force them to become smaller like African varanids, or go EXTINCT.

In fact, there's nothing THAT reptilian about dinosaurs, they're more like mammals anatomically and histologicaliy in more ways than I can think of. Dinosaurs are their own Class within Diapsida. Reptilia is not even a real Class because it presently includes turtles (Superclass Anapsida) as well as Lizards, Snakes & Crocs (Diapsida). But Birds are diapsids yet not "reptiles"... and early Synapsids like Dimetrodon are lumped in as "reptiles" just because they're cold-blooded sprawlers, even though mammals are also synapsids... Reptilia is an artificial grouping. Perhaps reptilia is really Amniota, but then mammals and birds would be "reptiles" too...

Better to have separate classes for Dinosauria/Ornithodira (including birds and pterosaurs), Crurotarsa (includes crocs and false crocs) within Archosauria, which has sphenodonts and lizards as sister clades within Diapsida. Turtles don't belong with any of these at all! Both Diapsida and Synapsida have warm-blooded members (dinosaurs and mammals). So the definition of reptiles is invalid.

But I don't think that a pack of raptors could EVER bring down a Sauroposeidon, even a young one... Unless it was less than a year old, and ACTUALLY the size of a polar bear. That scene was even faker than Jurassic Park. At least Spielberg realized that nobody messes with Brachiosaurus.

Anonymous said...

Or, nesting behavior could vary from species to species, as it does in modern animals. Some sauropods could give birth via the "leave-em somewhere" method, while others could attempt creching behavior. I mean look at the divergence in reproductive strategies between deer mice and house mice.

"Getting food for baby sauropods is easy, just bend your neck down, tear off some ferns and bring them back to the nest. In a few hours the babies can walk out of the nest and eat their own ferns."

The Auca Mahuevo specimens seem to suggest that the sauropod young were precocious, though. So they would have been ready to go the minute they hatched. Of course, most of the birds today that exhibit creching behavior also have young that are precocial.

But then again, one has to wonder how hidden an Auca Mahuevo nest would be when the whole area is pockmarked with nests. One would almost expect all the baby sauropods to be lunch meat right there, for if they came back to that spot year after year, the predators would just go right there and decimate the eggs.

"Raptors were pack hunters. They had the brain power, and all the evidence shows they brought down Tenontosaurus and ate the flesh, before any other carnivores could get to it."

Some of the larger ground-dwelling birds today live in groups, such as ostriches and rheas. However, we don't have any big, apex predator carnivorous birds out there to see if this holds true for obligate carnivorous birds, or just herbivores and omnivores (oh, if only the phorusrhacids were still around).

Perhaps the reason why gregarious, flying, carnivorous birds are so rare is because flight consumes so many calories, and the organisms need all the calories they can get just to power their flight (especially since most predator species don't succeed very often on the hunt). I mean, none of the vertebrate-eating bats I can think of hunt in packs (though I think some of them do roost together).

Anonymous said...

"For the first time since I can remember, these TV-special-calibur CG dinosaurs look better than the beasties in Walking With Dinosaurs"

I dunno. Walking with Dinosaurs seemed a bit more real, but I suppose that was more because the backgrounds in the special actually were real. But still, it was an improvement over most of the graphics seen in non-Walking With series.

"The juvenile Sauroposeidon, which looked about as big as an Astrodon given the trees around it, just kinda stood there while the raptors tore it apart."

Regardless of whether or not sauropods provided parental care initially for their young, wouldn't by that size the Sauroposeidon be travelling with other adults?

You know what we need? (In response to the uber-raptor and daikaiju Sauroposeidon remarks) A new "Walking With Dinosaurs" style documentary mini-series that chronicles the lives of the animals in the territory of a raptor pack in Oklahoma. Sort of like Raptor Red meets Meerkat Manor. Among the scenes that could be shown are a raptor hunt that ends in failure when one of the raptors gets thrown off and utterly trampled by a Tenontosaurus, or an enraged Sauroposeidon bull charging at an Acro who dares attack a female in estrus. Granted, it wouldn't be very fast, but when something that big is moving at you at even three miles an hour, that much momentum would be a force to behold.

Matt Martyniuk said...

"Raptors were pack hunters. They had the brain power, and all the evidence shows they brought down Tenontosaurus and ate the flesh, before any other carnivores could get to it."

What other carnivores lived alongside Deinonychus? If Deinonychus teeth are all that's found with the carcass, why does that mean they ate it before other carnivores did? Doesn't that mean they were just the only carnivores eating it? The only other theropods present in the Cloverly formation are ornithomimids and oviraptorids, all non-hypercarnivores. So the fact hat we only find dromaeosaur teeth at a kill site in an environment where dromaeosaurs were the primary, and possibly only, large carnivores is not informative to their social behavior.

Dr. Vector said...

From an early comment:

No wonder Matt Wedel claims on the show that out of thousands of babies "only two or three" survive to adulthood - with the kind of half-assed nest-digging the animation showed, I'm surprised ANY survived at all. I don't really agree with Matt's conclusion either. Sauroposeidon is only known from four adult cervicals, so any speculation about the babies is just that - speculation.

1) Yes, it is speculation, but Sauroposeidon was not specially created in a vacuum. We can surely draw on what we know about other sauropods until those inferences are shown to be incorrect; in fact, we have no other defensible choice.
2) Of the thousands of sauropod tracksites in the world, I know of only one that includes tracks from both hatchling-sized animals and adults. Admittedly we don't know very much about sauropod parental care or the lack thereof, but the lack of baby tracks with adult tracks, and the cases of age-segregated monospecific herds in the Morrison, China, and elsewhere, suggests pretty strongly that baby sauropods were on their own, and only joined the adults when they had attained substantial size.
3) None of the sauropod eggs discovered to date, on any continent, are very big, and they're never found in large groups. And sedimentological evidence indicates that the eggs were buried after they were laid. All of this suggests that mother sauropods laid many, many nests every season, each containing just a few eggs each, and left them. It's not airtight, but it's suggestive.
4) The idea that any mated pair of animals produces, on average, only a handful and probably only two successfully mating adults follows from the fact that world is not overrun with any given type of critter. If every mated pair produced ten reproducing adults, the population would explode geometrically. Darwin worked this out in The Origin.

For sauropods, combine the fact that the tiny nests we find simply cannot be the entire reproductive output of a female for a year, which implies many nests, with the fact that sauropods survived for a very long time without either going extinct or overrunning the world, and there is no escaping the conclusions that every mated pair (or every female with a succession of mates) DID produce thousands of eggs in her reproductive lifespan, on average, and that only two or three of those thousands of offspring survived to reproduce, on average.

Nima said...

I still wouldn't dismiss the likelihood of sauropods caring for their babies, at least until they could walk and eat on their own... but, yeah, I agree with Matt (Wedel, not Martyniuk) that a LOT of eggs were laid and most immature sauropods had to have been eaten to prevent a population explosion of animals that were untouchable as adults.

With eggs being so hard to tie down to any one species, it's possible at least SOME of them were crazy-r selected. But I think there could have still been some benefit in the parents bringing them their first meal.

Who knows why the sauropod eggs we find got fossilized... perhaps the area got flooded and the parents were unable to save the eggs. This fits with the fact that sauropods live on seasonal floodplains. If they produced huge numbers of nests in a year, it's conceivable at least SOME nests fell victim to flood sediment and were thus fossilized and "lost" to evolution forever. To me it's a bit odd we don't see MORE fossil nests considering how common seasonal floods were in sauropod habitats.

It may be that SOME sauropods were just highly eccentric nest builders and laid eggs in hazardous flood-prone areas. Look at enough female birds of any species, and you'll eventually find the odd kooky one that lays eggs in places where they have NO chance of survival, year after year. Literally "bird-brained".

The mere fact that the fossil eggs exist independent of fossil parents doesn't prove anything about sauropod parenting. I'm not saying it disproves anything either, but even if you assume that sauropods DID care for their young, you're NEVER going to find a Brachiosaurus crouched over her nest to incubate it like an Oviraptor! The fact is, any natural phenomenon (like a flood) powerful enough to kill and bury the adults would simply destroy the eggs, not preserve them. And any flood or other process that could bury a nest in sediment and preserve the eggs intact, probably would not kill the adults.

The VAST size discrepancy and physical difference between the adults and their eggs, and the impossibility of even the most caring sauropods parents personally incubating the eggs, means that no matter WHAT reproductive strategy sauropods had, nature still would be unlikely to preserve the adults and babies/eggs together at the same exact place and time.

Age-segregated herds indicate that by a certain age, at least some sauropods left the protection of their parents or other adults. But as for what they were doing before that, it's unknown.

The main reason why I'm skeptical of sauropods abandoning their eggs is that it's not a very dinosaurian trait. It's not typical of any other dinosaurs, or ANY warm-blooded animal - even an r-selected one, and even most cold-blooded reptiles don't do it! Crocs, gators, lizards, and snakes all watch over the eggs until they hatch. Crocs and gators go a step further and watch over the babies for a few weeks. Even a some of the more derived frogs and fishes look after their eggs. I don't think sauropods regressed backwards from the croc/gator level of parental care. That's just NOT the sort of pattern evolution shows, there's never been a documented case of it. Also, you don't need to abandon your eggs for most of the babies to get eaten later. Even if they take only 10 or 20 years to grow up, that's a LOT of time for things to get REALLY bad for them.

In any case, the animation with Sauroposeidon leaving its eggs UNCOVERED in the middle of nowhere with not even a hint of foliage around isn't very scientific at all IMO, and neither is the sequence of TWO Labrador retriever-sized Deinonychus taking down a Sauroposeidon that had already reached adult Astrodon size. Maybe two or three Acro's could do it. But not two little raptors. The dinosaurs themselves looked fine (though Sauroposeidon's neck needed to be longer) but their behaviors in the show were not realistic at all.

Dr. Vector said...

In any case, the animation with Sauroposeidon leaving its eggs UNCOVERED in the middle of nowhere with not even a hint of foliage around isn't very scientific at all IMO

Don't get me started. I talked with them at length about the evidence for buried eggs in sauropods.

and neither is the sequence of TWO Labrador retriever-sized Deinonychus taking down a Sauroposeidon that had already reached adult Astrodon size. Maybe two or three Acro's could do it. But not two little raptors.

Another grrrrr moment. In the talking head bit that goes with that shot, I was talking about little babies, like dog-sized, not an elephant-sized subadult like the one shown. It should have pulped those raptors.

The dinosaurs themselves looked fine (though Sauroposeidon's neck needed to be longer)

Once again we're in complete agreement! Every. Single. Time. I was asked to comment on the Sauroposeidon model, I said, "The neck is too short."

Makes me wanna holler.

Michael O. Erickson said...

"Crocs and gators go a step further and watch over the babies for a few weeks."

Actually, that's not quite right. A mother Alligator mississippiensis will care for her young for up to YEAR, sometimes more(!).

But I agree that while sauropod baby-rearing wouldn't have been too extensive, perhaps not even on par with an alligator's, this whole concept that sauropods were stupid worthless crappy peices of crap with the brain-power of a cotton swab, practically too moronic to perform basic bodily functions, and abandoning their young like sea turtles, is complete nonsense. I actually think that I remember Bakker griping about this very same stuff (pea-brained, baby-abandoning, sea turtle-like sauropods) in an article somewhere. I wish I could remember which one.

Nima said...

You have a great point about the gators, Mike! The thing is I get a bit sick of all this sauropod-bashing in popular entertainment. Sauropods are my favorite dinosaurs, and I just knew growing up that all the typical myths about them being dumb as a doorknob and unaware of where there rear was moving, etc. HAD to be false. They survived for as long as they did because they were WELL-adapted, not perpetually on the edge of dying from brain loss vestigialism.

It seems that sauropods are the last intellectual territory still occupied by outdated cold-blooded notions and stubbornly conservative professors - the last bastion of "dinosaur orthodoxy" as Bakker would have it. I've always envisioned sauropods as active animals that were pretty intelligent for their small brain size. Huge behemoths yes - but ones with very sensitive reflexes, good coordination, decent parental care, and smooth movements that didn't require stomping hard on every square inch of ground.

davidmaas said...

Thought so. Hulu and Discovery Channel are both screened here. "My region". Pfft.
After reading all these comments, though, I don't need to see it anymore anyway. LoL! Thanks guys - love the passion!

William Miller said...

As for the 'sauropods are stupid' thing ... could part of this come from the idea that they could 'cheat' since nothing was big enough to eat an adult sauropod? I've seen this claim ("adult sauropods were safe from predation" etc) repeatedly -- but it never made any sense to me. Is there evidence for it?

Sure, ludicro-gigantic monsters like Amphicoelias fragillimus might have been safe ... maybe. But Diplodocus, say, was only maybe three times the weight of Allosaurus/Epanterias amplexus or Saurophaganax ... and what about critters like Europasaurus.

A 35 kg wolf can take down a 700kg moose (even lone wolves have been known to do so, sometimes); 200kg lions can take down 4 t elephants. Is there any reason why a 2 t theropod couldn't take down a 30 t Giraffatitan?

Andreas Johansson said...

Don't miss Matt Wedel's comments over at SVPOW!:

http://svpow.wordpress.com/